For adhesive bonds in industry it is very common to employ pressure-sensitive adhesives (PSAs) in the form of adhesive transfer tapes. Generally the materials to be bonded to one another are of the same constitution. For certain applications, however, the materials to be bonded may differ in their chemical constitution. A significant influence on the adhesiveness of a material is exerted by the surface tension. Generally speaking, low-energy surfaces, such as polyolefins, for example, bond less well. If the desire is then to bond these materials to high-energy surfaces, it is usual to use double-sided PSA tapes which are composed of a carrier layer and coated with two different PSAs.
As far as the adhesive bond is concerned, however, the carrier layer does not possess any function. There is therefore demand for a bilayer PSA which incorporates this function of the double-sided PSA tape without the need for a carrier layer.
The object on which the invention is based, therefore, is that of specifying a bilayer PSA allowing adhesive bonding of materials differing in constitution, particularly materials having surfaces of different energy. It is also intended that a process for preparing such a PSA, and one use of such a PSA, should be specified.